Taking DDAVP through rhinal tube for "possible" diabetes insipidus... I void way more urine (2 to 3x as much) than I drink fluids/eat watery foods, and void frequently (also under treatment for OAB). DDAVP slows down the frequency/volume but after a few days on it, my blood pressure spikes way up, have intense headache, and frequency/volume increases. Taking lowest possible dose once/day. Anyone else have a similar experience?